Electrical connectors are used to form electrical connections between circuit boards that each contains a high density of electrical contacts. The contacts are arranged in a series of rows and columns in a contact field that covers a central portion of the flexible circuit. The contacts are closely spaced and a large number of contacts are included in a relatively small area.
One type of electrical connector used to interconnect circuit boards includes a flexible circuit having contacts located on one side of the flexible circuit. The flexible circuit is mounted on a backing member or support member on the opposite side of the flexible circuit across from the contacts. The support member carries a spring that faces the flexible circuit.
The support member is clamped against the printed circuit board with the contacts of the flexible circuit overlaying corresponding contacts of the printed circuit board. The spring is compressed between the support member and printed circuit board, the spring generating a spring force pressing the contacts of the flexible circuit against the contacts of the circuit board.
The flexible circuit is attached to the support member with some ability to “float”, that is, to move towards or away from the support member so that the portion of the flexible circuit carrying the contacts can remain against the spring when the spring is compressed. If the flexible circuit is not free to move with the spring, the spring may not compress properly and sufficient spring force may not be applied to all the contacts. Some of the contacts may not be pressed with enough force to form adequate electrical connections.
Conventionally, the flexible circuit is attached to the support member by a pair of rivets. The rivets are located on either side of the contact field and extend through rivet holes in the flexible circuit. The rivets may be designed to allow some float between the rivets and the flexible circuit.
Alignment pins also extend from the support member through the flexible circuit. The alignment holes are received in corresponding holes in the circuit board. The alignment pins and holes finely align the support member and the circuit board during assembly so that the contacts of the flexible circuit overlay the corresponding contacts of the circuit board.
Users may pull or tug on the flexible circuit to align the support member with the printed circuit board. The pulling or tugging force is transmitted from the flexible circuit to the rivets. The pulling or tugging force may cause tears in the flexible circuit at the rivet holes, particularly if the flexible circuit has low amounts of metal at the rivet holes.
Furthermore, the pulling or tugging force may press the flexible circuit against the rivets. The flexible circuit binds against the rivets, preventing the flexible circuit from freely moving with the spring. As a result, electrical connections between some pairs of electrical contacts may not be made or may be inadequately made.
Thus there is a need for an electrical connector having a flexible circuit that can better withstand pulls and tugs on the flexible circuit without tearing while allowing the flexible circuit to freely move with the spring during and after assembly.